衡山湘江大桥换索工程研究

Research on cables replacement for Hengshan Xiangjiang bridge

结合衡山湘江大桥斜拉索换索工程并基于最优化原理,介绍索力的优化理论,研究该桥的换索原则、方案及其施工工艺。研究结果表明:在换索工作中,主梁的弯矩、轴力,索塔根部弯矩、轴力均呈现周期性变化。拆除旧索,引起其它拉索产生内力重分布,索力变化明显。拆除某号拉索,影响最大的是与之相邻的2根索,索力均增大,其次影响最大是索塔背面相近拉索,索力均减小。而其他有关拉索在被更换时,该索的索力所受到的影响相对较小。拆除旧索,主梁线形及塔顶位移发生变化,近似呈现周期变化。根据最优化原理,调索最终(实测)索力与理论索力基本一致,最大误差约1%。

Based on an optimization theory,the optimization theory of cable force is introduced first.Take Hengshan Xiangjiang bridge as an example,the cables’replacement plan and principle and construction technology are detailed introduced.During the construction period of cables replacement,bending moment and axial force of main girder appear periodic changes as well as bending moment and axial force at the bottom of cable tower.When demolishing one old cable,other cables’tension has obvious redistribution.Replacement of a cable has the greatest influence on the adjacent two cables,their cable forces increase.It has the second greatest influence on similar cables on the back of cable tower,their cable forces are reduced.Other relevant cables are replaced,the impact of the cable is relatively small.During the construction period of cables replacement,the girder alignment and displacement at the top of the tower approximate change periodically.According to the principle of optimization,the finally completed cable force that is measured is basic consistent with its theoretical value,the maximum error is about 1%.